After generations in the shadows, socialism is making headlines in the United States. Today’s leftists hail from a long lineage of anti-capitalist activists in the United States, yet the true legacy and lessons of their most radical and controversial forebears, the American Communists, remain little understood. Historian Maurice Isserman focuses on the deeply contradictory nature of the history of the Communist Party USA (CPUSA), a movement that attracted egalitarian idealists and bred authoritarian zealots. Founded in 1919, the CPUSA fought for a just society in members organized powerful industrial unions, protested racism, and moved the nation left. This is the balanced and definitive account of an essential chapter in the history of radical politics in the United States.